What is the defining characteristic of undifferentiated cells, such as stem cells?

The defining characteristic of undifferentiated cells, such as stem cells, is symmetric division. This means that during the process of cell division, a parent stem cell can divide to produce two identical daughter cells, both retaining the same undifferentiated state as the original cell. This property is crucial for maintaining the stem cell population and ensuring a continuous supply of undifferentiated cells, which can later differentiate into various specialized cell types as needed for tissue repair and regeneration.

In contrast, asymmetric division occurs when a stem cell divides to produce one daughter cell that remains a stem cell while the other differentiates into a mature, specialized cell. While asymmetric division is a significant feature of how stem cells can give rise to differentiated cells, it is not what defines the undifferentiated state itself.

Progenitor cell replication refers to the process whereby progenitor cells (which are somewhat differentiated and have a more limited capacity to produce cell types compared to stem cells) divide. While progenitor cells do have replication and differentiation capabilities, they are not the focus when discussing the defining features of undifferentiated stem cells.

Therefore, symmetric division specifically captures the essence of how undifferentiated cells maintain their characteristics and self-renewal potential.